There are a few genuine gems buried within Shane Salerno's broad-yet-shallow documentary about J.D. Salinger.

Unlike its titular subject, who could map out the deepest recesses of the human psyche with a few surgically crafted paragraphs, Shane Salerno’s “Salinger” takes a rather long time to get to a rather simple point. After more than two hours of broad-yet-shallow biography, exhaustively researched yet often garishly presented, the film drops its bombshell: The notoriously reclusive author completed five works prior to his death, which are set to be published between 2015 and 2020. With that ultimate unveiling in mind, much of what precedes it ends up feeling like a long-winded carnival-barker pitch, even though a goodly number of genuine gems are buried within its noisy confines. Promoted alongside an identically named new biography, it should be a solid draw with arthouse crowds.

This Weinstein Co. release has been preceded by a rather unusual amount of mystery-box marketing for a documentary, with ads boasting such taglines as “What Happened to J.D. Salinger?” and “Uncover the Mystery.” The impending publication of his unread work is certainly momentous literary news — although, as Vladimir Nabokov’s “The Original of Laura” and Ralph Ellison’s “Juneteenth” illustrate, such holy grails of lost literature are often more interesting as mythical relics than as commercially available novels — but the mystery of Salinger’s life turns out to be anticlimactic from a narrative standpoint.

After he ceased publishing new work in 1965, the author, who died in 2010, seems to have spent the intervening years living a simple life in his Cornish, N.H., cabin, working on novels in private and occasionally striking up correspondence with a handful of teenage girls. For decades, devoted fans and literary paparazzi mounted pilgrimages to his home seeking gnomic kernels of wisdom and SLR snapshots, yet even those who actually made contact have little of interest to report. As one acolyte recalls being told by Salinger after tracking him down in the late ’70s: “I’m a fiction writer, not a counselor.”

Appropriately, the documentary is best when it focuses on Salinger as simply a writer, rather than the MacGuffin at the center of a potboiler, and Salerno, who spent nine years working on the production, certainly unearths some fascinating tidbits.

The film details Salinger’s early arrogance in pursuit of literary greatness; his horrific combat experiences in World War II; and his sudden elevation to, and hasty retreat from, literary celebrity. Without ever reading aloud from Salinger’s published prose, the litany of talking heads — including former associates, biographers, fellow writers like E.L. Doctorow and Tom Wolfe, and thesps John Cusack, Martin Sheen and Philip Seymour Hoffman — provide adequate context on the postwar maturation of Salinger’s style and the explosive impact of “The Catcher in the Rye,” which has sold more than 60 million copies since its 1951 publication.

Yet it’s difficult to get past the film’s restless, ill-fittingly bombastic style. Handicapped by the obvious dearth of images of the hermetic scribe, the docu resorts to displaying the same few black-and-white photos over and over, along with some rather ill-advised re-enactments, the worst of which repeatedly place a Salinger lookalike at a typewriter onstage with a screen projecting images of wartime carnage and past lovers buzzing busily behind him.

Jumpy cuts are frequent, well-worn period stock footage is prevalent, and Lorne Balfe’s wildly inappropriate score is almost comically out of sync with the subject, full of Zimmerian sub-bass pulses and saccharine string swells. There are moments when the film veers dangerously close to the sort of hyper-literal approach with which VH1’s “Behind the Music” series tackled the tales of Motley Crue and Def Leppard — the sentence “he stormed out the door” is accompanied by a cutaway to a slamming door, for example — and this is surely the first literary bio to include a Coldplay song and “South Park” clips over the end credits.

With that in mind, “Salinger” finds its most revealing anecdotes when it bothers to slow down. Erudite former paramour Jean Miller recalls first meeting Salinger at Daytona Beach when she was 14 and he was 30. After maintaining years of correspondence, and using her as inspiration for his peerless short story “For Esme — With Love and Squalor,” Salinger began to essentially date Miller when she was a college student, yet as soon as the 20-year-old finally initiated sex, Salinger froze her out. Salinger repeated a similar pattern with other girls — especially the mediagenic author Joyce Maynard, who also appears here — yet Miller provides the film’s most humanizing details, vividly describing Salinger’s conversational style and their nights together at home dancing along to “The Lawrence Welk Show.”

These epistolary obsessions with young girls are certainly eyebrow-raising, yet at no point is Salinger accused or even suspected of impropriety. Likewise, his shortcomings as a father and a husband seem to be due to simple neglect, and the closer the docu zooms in on the man behind the curtain, the more uncomfortable the focus starts to feel.

Needless to say, Salinger would have surely been horrified to see his personal life posthumously excavated to such a degree, and the filmmakers never really make a compelling argument that it should be. Despite bouts of armchair analysis, they fail to draw any meaningful connections between Salinger’s reclusivity and the themes of his work, and Salinger’s fellow Greatest Generation novelist-turned-longtime New England shut-in Thomas Pynchon is strangely never mentioned. Photographers interviewed here proudly spin tales of hiding in bushes or staging stakeouts in cars to snap a few photos of Salinger retrieving his mail or walking his dog, yet no blurry image of the aging man or revelation of his personal quirks can hope to equal the resonance of a single one of his sentences, and one waits in vain for the filmmakers to acknowledge this.

I can see why Salinger wanted nothing to do with Hollywood… what a disgusting thing to do to a dead man; who prized his work and privacy above all else; then to be subjected to this… Christ! If he came back from the dead he’d surely commit suicide.